Manufacture of anthranol.



rrE s'rA'rns PATENT OFFICE;

FRITZ SINGER, OF OFFENBACH-ON-THE-MAIN, GERMANY, ASSIGNOR TO THECORPORA- TION OF CHEMISCHE FABBIK GRIESHEIM 'ELEKTRON, OFFRANKFORT-ON-THE- MAIN, GERMANY.

-MANUFACTURE OF ANTHRANOL.

No Drawing.

Specification of Letters Patent.

Application filed February 7, 1911 Serial No. 607,154.

Patented July 25, 1911.

To aZZ whomtt may concern:

Be it known that I, Fnrrz SINGER, doctor of philosophy, chemist, asubject of the German Emperor, and resident of Offenbachon-the-Main, inthe Grand Duchy of Hesse, Germany, with post-oltice address Mainstrassc179, have invented new and useful Improvements in the h'lanufacture ofAn thranol, of which the following is a specification.

Liebermann has described in the Berw/ize (fer Dmusolzen Uizcm'e'sclz enGesellsnizuft vol. 20 page 1854 a process for the manufacture ofanthranol consisting in reducing anthraquinone in glacial acetic acid bymeans of tin and hydrochloricacid. This process can he performedsmoothly but it is too expensive on a commercial scale. More profitableon a commercial scale is the process described in the specification ofGer-- man Letters Patent No. 201542, consisting in reducinganthraquinone, dissolved in concentrated sult'uric acid, by means ofmetals.

Now I have found that anthranol can be obtained in a more advantageousmanner by reducing antln'aquinone, suspended in a liquid with ferroussalts. The reduction may .he performed preferably in aqueous or.

acetic suspension. The ferrous salts can also he produced during theprocess of reduction. 'lhere'fore it can he used as reducing agentlcrrous chlorid alone, or iron and hydrochloric acid, or iron andt'crrous chlorid for instance.

It is rccommendahle to carry outthe process in acetic acid suspensionprovided that the produced anthranol is to he worked up in the aceticacid solution like in the production of dianthronc for instance. By add-1 color.

dissolves in caustic sodaclye with yellow:

After cooling the precipitate is filtered oil andwashed with water. Theresidue is dissolved in caustic soda lye and strained directly intohydrochloric acid. The precipitated anthranol is worked up in the wellknown manner. It has a melting point of 152, dissolves in caustic sodalye with yellow color and crystallizes from diluted acetic acid in shapeof needles.

If the process is carried out in acetic acid suspension the heating canhe performed in an open vessel or on using a reflux-condenser.

Now what I claim and desire to secure by Letters Patent is thefollowing:

The process for the manufacture of anthranol consisting in treatinganthraquinone, suspended in a liquid, witlf ferrous salts.

In testimony, that I claim the foregoing as my invention, I have signedmy name in presence of two witnesscs,thistwenty-fourth day of January1911.

- FRITZ SINGER. \Vitnesses HERMANN WVEST, ltoinca'r 131mm.

